1. Field of Invention
This invention relates generally to crib or bed sheets, and in particular to an inexpensive and disposable fitted sheet that snugly conforms to a standard crib or bed mattress, the fitted sheet being made from a single flat blank of non-woven material in a manner that lends itself to automation.
2. Prior Art:
Infants and very young children are normally bedded down in a crib which is a bedstead enclosed by high slatted sides. The crib is provided with a mattress which is protectively covered by a crib sheet. An infant or young child occupying the crib will almost invariably wet or soil the crib sheet; hence the crib sheet must be repeatedly washed. The ordinary crib sheet is fabricated of woven cotton or other natural or synthetic textile fibers, or a composite thereof. In fitting the sheet to the mattress, one must fold and otherwise manipulate the sheet to form corners which conform to the corners of the mattress.
The same situation is encountered with ordinary bed sheets used in hospitals, nursing homes and in other places where the occupant of the bed is incontinent and therefore soils the sheet covering the bed mattress. Such crib sheets must be washed and sterilized after every use, a procedure that adds to operating expenses.
In a crib, the mattress is below the level of the slatted sides even when the sides are lowered; hence it is more difficult to form crib sheet corners than when forming corners on ordinary bed sheets. To overcome this difficulty, it is known to provide crib sheets as well as bed sheets with preformed corners, as disclosed, for example, in the Bogle patent 4,161,044. In making such fitted sheets, Bogle cuts a sheet to create a main rectangular panel and side and end panels which depend from the main panel and are sewn thereto to form right angle corners. The manufacture of such a fitted sheet requires cutting and sewing operations and is therefore relatively expensive.
When the infant or child occupying the crib is ill, then conventional washing procedures may not be sufficient to insure sterility and avoid possible reinfection because of inadequately cleaned crib sheets. It is for this reason that in a serious illness, even though conventional crib sheets are relatively costly, the usual practice is to dispose of the sheets after a single use.
Another problem encountered with crib sheet arises when one is traveling with a child. While many hotels and motels supply cribs having mattresses and crib sheets, one has no idea who previously occupied the crib, or whether the crib equipment is sanitary. Hence the better practice in this situation is to bring along fresh and clean crib sheets and to thereafter dispose of these crib sheets. But the cost of conventional crib sheets is such as to render this practice extravagant, particularly if more than one child is involved.
The above-identified copending patent application discloses a fitted crib sheet that is created without any cutting or sewing operations from a single blank of washable, synthetic plastic material. This blank is converted into a three-dimensional fitted sheet by folding operations and ultrasonic sealing. Because the fitted sheet makes use of inexpensive material and can be made at low cost, one may dispose of the sheet after a single use, as may be desirable when sterility is of great concern, or where it is inconvenient to wash the sheet so that it can be reused.
In the fitted sheet disclosed in my copending application, the sides of a single rectangular blank are folded in on longitudinal fold lines and its ends are folded in on transverse fold lines. Then the corners of the blank are folded in on diagonal fold lines to form triangular folds that are ultrasonically sealed to the folded-in ends, thereby defining a boxlike fitted sheet having reinforced right angle corners and sides and ends coextensive with those of the mattress. Each end of the fitted sheet is creased to form puckers that are joined to an elastic strip to render the end stretchable whereby the fitted sheet conforms snugly to the mattress.
A fitted crib sheet so formed is easy for a user to apply to a mattress, and it conforms snugly thereto so that it is not dislodged by a restless occupant who thrashes about the crib or bed. However, because the fitted sheet is developed by folding in the sides as well as the ends and the corners of the blank, these operations do not lend themselves to automation, as a consequence of which the crib sheet is relatively expensive to manufacture.
Thus, paper bag-making machines are available in which a web of paper drawn from a large reel is continuously fed into a folder station wherein the sides of the web are folded in before the web is then cut into individual folded-in pieces which are further processed to form a bag. It is not possible to use such machines to carry out all of the necessary folding operations using non-woven sheeting rather than paper in making a crib sheet of the type disclosed in my pending patent application, for one cannot with this machine also provide the required end folds and the diagonal folds at the corners.